Buoy with buoyancy produced by liquefied gas vaporization



April 1968 H. o. BERTEAUX ETAL 3,376,588

BUOY WITH BUOYANCY PRODUCED BY LIQUEFIED GAS VAPORIZATION Filed Oct. 24,1965 INVENTORS A TTORNEYS Unit States Patent 3,376,588 BUOY WITHBUOYANCY PRODUCED BY LIQUEFIED GAS VAPORIZATION Henri 0. Berteaux,Pompano Beach, Fla, and Thomas K. Brown, Chicago, 111., assignors toChicago Bridge & Iron Company, Oak Brook, Ill., a corporation ofIllinois Filed Oct. 24, 1965, Ser. No. 504,621

9 Claims. (Cl. 9-8) ABSCT OF THE DISCLOSURE Provided is a buoy which canbe used to develop buoyancy in water. The buoy comprises a shell whichmay be either rigid or non-rigid and which is stabilized to maintain anupright position in Water. A chamber associated with the shell forholding a liquefied gas, means for delivering vaporized gas from thechamber to the interior of the shell, and port means on the shellthrough which ballast and water in the shell is expelled to thesurrounding body of water as the ballast water is displaced by expandinggas received from the chamber.

This invention relates to apparatus for achieving buoyancy in water.More particularly, this invention is concerned with a buoy-type Vehiclefor supporting objects at least partially submerged or totally submergedin water. In addition, the invention is concerned with a buoy which candescend to great depths in a body of water and then return upwardly,such as to the surface of the water, without extraneous assistance.

In the past, buoyancy problems in water were fairly simple and weresatisfactorily handled by means of hollow vessels which could withstandthe rather moderate pressures of water down to depths of about 200 to300 feet. In more recent times, the seas have been penetrated to fargreater depths, and the farther down an object goes, the more difiicultit becomes to maintain buoyancy and withstand the pressures involved. Asa result, han- I dling and retrieving of equipment has become morecomplicated. Furthermore, vessels for buoyancy at the great depths mustgenerally be so heavy to achieve the needed strength as to be costly tomake and transport, as well as being difficult to handle satisfactorily.

One solution to the buoyancy problem was employed by Piccard in hisbathyscaph in which he employed gasoline in a rather thin-walled vesselto obtain buoyancy control. The gasoline was lighter than water and onlya thin-walled vessel was required to contain the gasoline because theinternal pressure balanced the external pressure. Gasoline, however, isa flammable liquid and thus is dangerous to employ in routineoperations. Also, the difference in densities between water and gasolineis a limiting factor on this method of achieving buoyancy.

Compressed gas in bottles or used in various types of pumping systemsalso have been employed but such methods are of low eificiency at depthsbeyond a few hundred feet.

According to the present invention, there is provided a buoy or vehiclefor achieving buoyancy in water and a method of using such a buoy tosupport an object in water. The buoy provided by this invention achievesbuoyancy by the conversion of a liquefied gas to the vapor or gaseousstate, particularly through heat transfer from the surrounding water andthe liquefied gas.

This buoy, which can be used in a body of water, such as an ocean, lakeor river, to develop buoyancy comprises a rigid or non-rigid shell,advisably stabilized to maintain an upright position in water, a chamberassociated with the shell for holding a liquefied gas, means fordelivering vaporized gas from the chamber to the interior of the shell,and port means on the shell through which ballast water in the shell isexpelled to the surrounding body of water as the ballast water isdisplaced by expanding gas received from the chamber.

The invention will be further described in conjunction with the attacheddrawings in which:

FIGURE 1 is a vertical section through a buoy provided by thisinvention, showing the inside of the shell full of water;

FIGURE 2 is a vertical section on a reduced scale, similar to FIG. 1except that part of the water in the shell has been displaced byvaporized gas from the liquefied gas contained in the chamber;

FIGURE 3 is similar to FIG. 2 except that essentially all of the waterin the shell of the buoy has been expelled by displacement by gasgenerated by vaporization of the liquefied gas in the chamber throughheat exchange with the surrounding water; and

FIGURE 4 is a plan view of the vehicle as shown in FIGS. 1 to 3.

In each of the figures of the drawing, the same reference numbers willbe used for similar parts.

In FIGS. 1 to 4, it will be seen that the buoy is comprised of a shell10 shown as rigid in the drawing. The shell can be rigid and made of anysuitable material, particularly metal or plastic, including plasticreinforced with glass fibers, or it can be nonrigid such as a balloon,which is expansible or nonexpansible, made of rubber, polyethylene,water-proof cloth or other suitable material. The upper portion of theshell has a rounded nose 11 of somewhat reduced diameter compared to theshell 10. Both the nose 1 1 and the shell 10 are of generallycylindrical'shape and axially positioned to each other. Fins 12 areprovided on the lower portion of the shell to stabilize the buoy andmaintain it in a more or less vertical position when it is descending inwater or is being raised by buoyancy developed through vaporization ofthe liquefied gas as will be further explained subsequently. Fins of asymmetrical shape with respect to the buoy shell can be used, ifdesired, or if the buoy is properly ballasted, the fins can beeliminated completely. The number of fins provided can be varied asdesired although three vertical fins equally spaced about the peripheryof the shell are suitable. The fins desirably extent below the bottom ofthe shell to provide a stand means for supporting the buoy upright on aload-bearing surface. Inside of shell 10, in the bottom portion thereof,is located enclosed chamber 13 shown here as formed by hollow sphericalmember 20. The chamber can be surrounded with insulation 14 aroundsphere and the insulation coated or further surrounded with anappropriate shell or membrane 21 to keep water or other liquids fromcoming in direct contact with the insulation. Instead of placinginsulation around sphere 20, a surrounding shell may be used and thespace between it and sphere 20 evacuated, thus forming a vessel in thenature of a DeWar flask. Alternatively, an evacuated area containinginsulating material can be used to retard heat transfer. Leading fromchamber 13 is conduit 16 which conveys gas vapor from the chamber to theupper inside area of the buoy.

On the top of nose 11 is provided cap 17 which can :be removed andreplaced in a water-tight manner to seal an orifice leading inside thenose. Instead of a cap 17, a suitable valve may be used. Positionedabout the periphery of shell 10, along the lower part thereof, are ports18 which provide passages between the inside of the shell and theoutside. On the bottom of the buoy is attached a hook 19 having springto prevent accidental unhooking. The book can be used for attaching apayload to the buoy in order that the buoyancy developed by the buoy canbe used to perform a useful task, such as raising an object upwardly inthe sea.

In operating the buoy, cap 17 is first removed and by means of along-stemmed funnel, a liquefied gas is poured into the chamber 13 untilit is at least partially full. The filling funnel is then removed andcap 17 repositioned loosely in place. The buoy is then placed in waterwith the nose portion 11 projecting above the surface. Water ballastenters shell through ports 18 and displaces at least part of the air inthe buoy but desirably up to the water surface as shown in FIG. 1. Cap17 is secured in a liquid-tight manner and the buoy will then partiallysink or descend in the water according to the inherent weight of thebuoy when ballasted with water. Unless heat exchange between the sea andthe liquefied gas in the chamber 13 is regulated to be rapid, and thebuoy is adequately ballasted with water, the buoy will sink to a greatdepth before buoyancy is developed sutficiently to overcome the downwardforce of the buoy due to its inherent weight in water. Since most seasare at least 40 F. or higher, there is sufiicient latent heat in the seato effect heat transfer with the liquefied gas and vaporize it. Theresulting vapor is conveyed by pipe 16 up into the inside of noseportion 11. The vapor volume continues to increase as heat exchangecontinues, thereby causing displacement of water from shell 10. As shownin FIG. 2, water has been displaced from approximately one-half of theinside of the shell, while in FIG. 3 essentially all the water has beenexpelled from inside shell 10 through ports 18 leaving the interior ofthe shell 10 full of vaporized gas. By displacing the water from shell10, the buoy has achieved buoyancy equal to the amount of waterdisplaced. Accordingly, the buoy can raise a total load approximately upto the amount of buoyancy generated by displacement of the water fromthe inside shell 10'.

The liquefied gas used in the buoy is to a considerable extent a matterof choice since a number of liquefied gases can be employed, includingliquid nitrogen, liquid hydrogen, liquid propane, liquid butane, liquidhelium and liquid oxygen. The rare gases, such as argon and neon aregenerally not employed because of their expense. In general, those gaseswhich when liquefied are considered cryogens constitute the mostsuitable group for obtaining the advantages of this invention.Presently, liquid nitrogen is the preferred liquid gas for use inthebuoy. Since cryogens are considered the liquefied gases of choice,the buoy of this invention might properly be named a cryofioat when itobtains its buoyancy by vaporization of a liquid cryogen.

Oxygen can be used below water to sustain life of a human crew in avessel and thereafter employed for etfecting buoyancy in a buoy of thisinvention. Further more, propane or methane together with oxygen can beused for welding under water and thereafter used to obtain. buoyancy.

Since the internal pressure on the buoy is in approximate balance withthe external water pressure at all times, the shell 10 need only be athin wall and can be rigid or non-rigid but capable of withstandinghandling and the temperatures to which it is subjected. This is trueeven though water is expelled from the buoy by vaporized gas in creatingbuoyancy since the pressure of the vaporized gas is only slightly higherthan the pressure of the sea at the location of the buoy below thesurface at any particular time or at any particular place.

The buoy may be used as a conventional float for supporting submerged orpartially submerged objects, as an undersea buoy for supportinginstrumentation at a predetermined depth in the sea with whateverancillary anchoring means is required, for transporting prospecting andmining equipment and tools to and from the bottom of a sea and also forrescue operations.

The invention also provides a method for raising objects from below thesurface of a water body. The fioat or buoy of this invention will sinkby gravity to a great depth, such as to an ocean floor, where it can beconnected to a submerged object. The object, thus, be-. comes a payloadcargo to be raised toward the water surface. Through heat exchange, thebuoyancy of the buoy increases as already described cargo objectupwardly. The sea water in the buoy can be considered as the ballast. Onthe way down, the float contains a small volume of liquefied gas and alarge volume of water ballast. On the way up, the buoy rises because itcontains a large volume of vaporized gas and little, if any, waterballast.

The speed at which buoyancy is developed in the buoy, at or over anyportion of its mission, isaregulated by controlling the heat exchangerate. This can be done by adjusting the amount of insulation orevacuated area around i the chamber containing the liquefied gas. Forrapid heat exchange the insulation can be eliminated completely. Also,it is feasible to provide an auxiliary heater operated by electricstorage batteries or bycombustion of a carbonaceous fuel, such as liquidpropane, to speed vaporization of the liquefied gas in chamber 13. Inaddition, the ascent of the buoy can be controlled by suitablepositioning of the outlet ports 18. Also, by varying or adjusting theposition of the ports, a predetermined limit can be imposed upon thebuoyancy of the buoy by restricting the amount of gas retained in theshell 10. The rate of ascent can be regulated in this way as can thetotal buoyancy be controlled to hover the buoy at a specific depth belowthe surface.

The buoy is so constructed that it is capable of floating upright inwater when the water ballast is low. This per 'mits charging of the buoywith liquefied gas while the buoy is floating. Thereafter, it can beflooded internally with ballast water for descent into the water.

Additional buoyancy is achieved by the accumulation of ice on the buoyexterior because of the low temperature at which the liquefied gas isstored and vaporized.

Various changes and modifications of the invention can t prising a shellstabilized to maintain an upright position i in water, a chamberassociated with the shell for holding a liquefied gas, means fordelivering vaporized gas from the chamber to the interior of the shelland port means on the shell through which water in the shell is expelledto the sea as it is displaced by expanding gas received from thechamber.

2. A buoy for use in the sea to develop buoyancy comprising a rigidshell stabilized to maintain an upright position in water, a chamber inthe shell for holding a liquefied gas for heat exchange relationshipwith. the sea when submerged, means for delivering gas generated in thechamber to the interior of the shell, and port means near the lower partof the shell through which water in the shell is expelled to the sea asit is displaced by expanding gas received from the chamber.

3. A buoy according to claim 1 in which the chamber is provided withmeans to retard heat transfer from outside to inside the chamber.

4. A buoy according to claim 2 in which the chamber is insulated toretard heat transfer from outside to inside the chamber.

5. A buoy according to claim 1 in which the chamber is surrounded by anevacuated area to retard heat transfer from outside toinside thechamber.

6. A buoy for use in the sea to develop buoyancy comprising a rigidcylindrical shell having a rounded upper nose portion and stabilizingfins on the lower portion, a.

and lifts itself and the livering vaporized gas generated in the chamberto the interior of the shell, port means near the lower part of theshell through which water in the shell is expelled to the sea as it isdisplaced by expanding gas received from the chamber.

7. A buoy according to claim 6 in which the chamber is provided withmeans to retard heat transfer from outside to inside the chamber.

8. A buoy according to claim 1 in which the shell is rigid and thechamber is provided with means to retard heat transfer from outside toinside the chamber.

9. A buoy for use in the sea to develop buoyancy comprising:

a rigid cylindrical shell having a rounded upper nose portion andstabilizing fins on the lower portion;

a spherical chamber postioned in the lower portion of the shell forholding a liquefied gas for heat exchange relationship with the sea whenthe buoy is submerged;

insulation around the spherical chamber to retard heat transfer fromoutside to inside the chamber;

a conduit running from the chamber to the upper inner nose part of theshell for delivering vaporized gas generated in the chamber to theinterior of the upper nose portion of the shell;

port means near the lowermost part of the shell through which water inthe shell is expelled to the sea as it is displaced by vaporized gasreceived from the chamber;

and a removable and replaceable cap sealing an orifice in the noseportion which permits liquefied gas to be poured therethrough, when thecap is removed, into the conduit for filling the chamber.

References Cited UNITED STATES PATENTS 1,300,943 4/1919 Farnham 114-533,046,925 7/1962 De Lisio 1l4-54 3,070,059 12/1962 Testa 114-54 20MILTON B'UCHLER, Primary Examiner.

T. MAJOR, Assistant Examiner.

